The study assessed the risk of premature death among middle-aged people who scored differently on four "healthy lifestyle factors" and found those who scored low had the same risk of death as those who scored high but were significantly older: in the case of women, 15 years older and in the case of men, just under 8.5 years.
The four healthy lifestyle factors were: smoking, physical activity, nutritional pattern and body weight.
Author Piet van den Brandt, Professor of Epidemiology at Maastricht University, told the media that:
"Very few research studies worldwide have analysed the relationship between a combination of lifestyle factors and mortality in this way."
"Furthermore, the effects of a Mediterranean diet were more evident in women than in men. Within this diet, nuts, vegetables and alcohol intake had the biggest impact on lower mortality rates," said van den Brandt.
For the study, van den Brandt used data on diet and lifestyle habits of 120,852 men and women aged 55 to 69. The data came from the Netherlands Cohort Study (NLCS), which started in 1986 and was set up by researchers at the Department of Epidemiology at Maastricht University and TNO Quality of Life.
From this information, van den Brandt calculated a "healthy lifestyle" score (0 to 4 points: least healthy to healthiest), comprising four factors:
- Not smoking.
- Being physically active for at least 30 minutes a day.
- Having a healthy body weight (body mass index, BMI between 18.5 and 25; this is the ratio of weight to the square of height in metric units).
- Adhering to a Mediterranean diet (high intake of fruits, vegetables, legumes such as beans, nuts, whole grains, fish, monounsaturated instead of saturated fat, and low intakes of meat and limiting alcohol to 0.5 to 2 glasses a day).
The results showed a strong link between healthy lifestyle and deaths in men and women, in that the highest (healthiest) scores were tied to the lowest risks of death.
However, adherence to the Mediterranean diet was significantly related to lower deaths among the women in the cohort but not significantly among the men.
Comparing the women with the least healthy scores to those with the healthiest, the risk of death was over 4 times higher (HR 4.07, 95% CI: 2.59, 6.40; P-trend <0.001). For men it was more than 2.5 times higher (HR 2.61, 95% CI: 1.79, 3.80; P-trend <0.001).
Expressed as an "aging effect", the least healthy women had the same risk of death as the healthiest women who were 15.1 years older (95% CI: 9.9, 20.2 y). In men this effect was 8.4 years (95% CI: 5.0, 11.8 y).
The study concludes:
"This study suggests that adherence to 4 modifiable healthy lifestyle factors can substantially reduce premature mortality in women and men. "
Van den Brandt said not only did the risk of dying appear to be influenced by the healthy lifestyle score, but the biggest reduction in premature death was in people with low or medium levels of education.